This is an English locational surname recorded in the varied spellings of Cawston, Causton, Cawstan, Corston, Corsten and in the rare (apparently Cornish spelling of) Koerstin, one Richard Koerstin being so recorded at St Martins on Looe Bay, on September 10th 1727. There are a number of villages called Cawston and Corston, the name means 'the farm of Kalf', the latter being a pre 8th century Viking name, in East Anglia and the West Country, with one example in Pembroke, West Wales. Curiously only the East Anglia villages seem to have given origination to the surname, although with locational surnames tracing the precise origin from a potential of six or seven sources, is often very difficult and sometimes impossible. The name spelling in one form or another dates back to at least the famous Domesday Book of 1086, when Heraldus de Caustuna appears in the register as holding lands in the county of Suffolk. Other early land charter recordings include examples such as Stephen de Causton of Edegefield, Norfolk, in the 'Feet of Fines' rolls for the year 1250, and Richer de Causton is similarly recorded in the year 1265. Later examples from church records include Thomas Cawston, who was baptised at St James church, Clerkenwell, London, in 1633, whilst James Causton was buried at St Michael's Cornhill, London, in 1711. On January 9th 1757, William Corstan was a witness at St Botolphs without Aldgate, London, and on August 4th 1781, John Corston married Jane Mowate, at St Dunstans in the East, Stepney. The first recorded spelling of the family name is shown to be that of William de Caustan, which was dated 1125, the rolls and charters of the county of Norfolk, England, during the reign of King Henry 111, known as' The Frenchman', 1216 - 1272. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.